For the universal multiaxial machining of complex workpieces in a chucking device, carrier devices and workpiece table arrangements have been known for a long time in various embodiments with which the workpiece clamped on a workpiece table may be pivoted by 90° from a horizontal to a vertical position and vice versa. If the workpiece table arrangements contain rotationally driven rotary tables, it is possible to perform five-axes machining operations by these motor-driven pivoting movements, that is, the top surface and all sides of the workpiece can be approached and machined one by one by the machining tool in continuous succession.
European patent publication, EP 1 882 544 A, discloses a drilling and milling machine configured for five-axis machining of workpieces that comprises a generic carrier device including a workpiece table arrangement. The workpiece table may be pivoted by a motor from a horizontal into a vertical position, with inclined positions also being possible. In this carrier device, guide rails on pedestals are provided inside next to the two side walls of the machine frame, on which two carriages are arranged so as to be synchronously displaceable by means of electric linear motors. In both carriages a bridge-like console is pivotably supported whose middle part offset with respect to the pivoting axis forms the support for a rotary workpiece table. Direct drive electric motors, which are installed in both carriages, are used to pivot the bridge-like console. The drilling and milling machine has a vertical milling head as the machining unit which is displaceably guided in the horizontal X coordinate axis and in the vertical Z coordinate axis on the machine frame. The travel movements in the horizontal Y coordinate axis are performed by the workpiece carrier device. Due to the support of the bridge-like pivoting console on both sides in the two dimensionally stable carriages, it is possible to achieve sufficiently high rigidity even in case of relatively large diameters of the workpiece table. However, the relatively high space requirement of the table arrangement and the considerable technical efforts can be a disadvantage, for example, because of the two electric direct drives in the carriages which need to have considerable dimensions for pivoting the bridge-like console together with the workpiece table and the chucked tool that may have a heavy weight.
In addition to that, European patent publication EP 0 712 682 A discloses a drilling and milling machine in a gantry constructional style configured for machining workpieces in five-axes, whose machine stand has two spaced-apart parallel side walls. A pivotable workpiece carrier device is provided between these side walls, whose bridge-like pivoting console carries a rotationally driven workpiece rotary table and is directly supported in the side walls of the machine stand via two lateral horizontal bushes. Electric drives that are installed on the outside of the lateral walls are used to pivot the console about the common support axis. The bridge-like console has a middle part offset with respect to the common rotational and supporting axis on which the workpiece rotary table is supported. Both sides of this middle part are firmly connected to the inner ends of the bearing bushes provided in the side walls. Instead of the pivotable workpiece carrier device a stationary workpiece table may also be used in this known milling and drilling machine which is laterally attached to pedestals formed on the inner sides of the lower regions of both side walls.
Another machine tool for the five-axis milling machining of workpieces is described in PCT publication WO 2006/072356 A. The workpiece table used in this machine tool has a rotating/pivoting unit whose rotating unit is disposed in a pocket-like recess provided in the center area. The rotating unit is firmly connected to the pivoting unit at a front face thereof via a lateral inclined support. The placement of the rotating unit in the pocket-like recess is to lower the overall structural height of the workpiece table arrangement.